Research Finds Thousands of Sea Turtles Killed by Costa Rica Longline Fishery

Studies conducted by researchers from Drexel University, Costa Rican conservation group Pretoma, and US conservation group The Leatherback Trust found that the longline fishery of Costa Rica is responsible for the deaths of thousands of endangered sea turtles, and potentially putting fish populations affected by the fishery at risk of collapse.

The data came from scientific observers on longline fishing boats over a decade (1999-2010) who recorded every species that was pulled from the sea, including target species and bycatch. During the study period, roughly 699,000 olive ridley and 23,000 green sea turtles were recorded as bycatch from fisheries that targeted mahi mahi, marlin, sharks, and tuna.

Concurrent data recorded on olive ridley nesting populations on Costa Rica’s Ostional Wildlife Refuge, an important nesting ground for the species, showed declines in nesting populations were directly linked to longline fishery catches. Seasonal closures for the fishery, as well as the establishment of marine protected areas, were recommended by the research team in order to mitigate damages. They also called for INCOPESCA, the fisheries management agency of the Costa Rican government, to begin enforcing national laws that were enacted several years ago and realize their current methods are unsustainable.